Protein Concentration (BCA/Bradford standard curve) implementation

Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

Record owner

Guth Instruments

Lifecycle

verified-with-binding-errata

Evidence ID

t6-097

Effect

Computation or source lookup only

Input and validation requirements

The regression is undefined when all standard concentrations are identical, and the specification does not state validation behavior for negative inferred concentrations or ambiguous signed absorbance values. The specification also has no actual multi-regime formula branch despite a potential slope-sign boundary.

Required corrections

[
  {
    "vector": 2,
    "field": "R_squared",
    "wrong": 0.9964474245,
    "correct": 0.9991119005,
    "cause": "slope/intercept exact, R2 slipped (SSE=1e-4, SST=0.1126 -> 0.999112)"
  }
]

Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

{
  "inputs": {
    "standard_concentrations_mg_per_mL": [
      0,
      1,
      2,
      3
    ],
    "standard_absorbances_AU": [
      0.05,
      0.25,
      0.45,
      0.65
    ],
    "sample_absorbances_AU": [
      0.35,
      0.05
    ]
  },
  "expected_outputs": {
    "slope_m_AU_per_mg_per_mL": 0.2,
    "intercept_b_AU": 0.05,
    "R_squared": 1,
    "sample_concentrations_mg_per_mL": [
      1.5,
      0
    ]
  },
  "working": "The points lie exactly on A=0.20c+0.05: for c=0,1,2,3, predicted A values are 0.05, 0.25, 0.45, 0.65. Therefore m=0.20 AU/(mg/mL), b=0.05 AU, and every residual is 0, so SSE=0 and R²=1−SSE/SST=1. For sample A=0.35: c=(0.35−0.05)/0.20=0.30/0.20=1.5 mg/mL. For sample A=0.05: c=(0.05−0.05)/0.20=0/0.20=0 mg/mL. The second sample is the zero-concentration/intercept edge case."
}

Other records

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json
• evidence-tranche6/tranche6-results.json
• tranche errata record